Table 1.
Available studies examining the glucose-lowering effects of preload-based nutritional interventions.
| References | n | Preload | Timing | Control | Test meal | Effect on postload glycemia |
|---|---|---|---|---|---|---|
| TYPE 2 DIABETES | ||||||
| Gentilcore et al. (22) | 6 | 30 ml olive oil | −30′ | 30 ml water | 65 g powdered potato + 20 g glucose + 250 ml water | Delayed glucose peak |
| Ma et al. (23) | 8 | 55 g whey protein + 350 ml water | −30′ | 350 ml water | 65 g powdered potato + 20 g glucose + 250 ml water | Glucose iAUC −51% |
| Chen et al. (34) | 10 | 30 g soya beans + 75 g yogurt | −120′ | None | 51 g carbohydrate + 4.8 g fat +5.8 g protein | Glucose iAUC −36% 2 h glucose −9% |
| Clifton et al. (35) | 24 | 17 g whey protein + 3 g lactose + 5 g guar + 150 ml water | −15′ | 150 ml water | 2–3 slices of bread + jam and margarine, tea/coffee | Peak glucose −1.4 mM Mean glucose −0.8 mM |
| Jakubovicz et al. (36) | 15 | 50 g whey protein + 250 ml water | −30′ | 250 ml water | High-glycemic index breakfast (353 kcal) | Glucose AUC −28% |
| Li et al. (28) | 30 | 18 g Inzone ® Vitality (7.6 g protein + 1.8 g fat + 1.6 g fiber + 5.2 g carbs) + 150 ml water | −30′, each meal,12 weeks | None | Normal diet | HbA1c −0.3% 2 h glucose −14% |
| Ma et al. (37) | 7 | 25 g whey protein + 100 ml water | −30′, 4 weeks | 100 ml flavored water | Normal diet Acute studies: 65 g potato + 20 g glucose + 250 ml water |
Fructosamine −9%*
Peak glucose −5*-9% |
| Shukla et al. (33) | 11 | 150 g chicken meat + 170 g vegetables | −15′ | Reverse order | 90 g ciabatta bread + 120 ml orange juice |
Glucose iAUC −73% 2 h glucose −7% |
| Trico et al. (18) | 10 | 50 g parmesan cheese + 50 g egg + 300 ml water | −30′ | 500 ml water | 75 g oral glucose | Glucose iAUC−49% |
| Kuwata et al. (31) | 12 | 100 g mackerel fish or 79 g beef meat | −15′ | Reverse order | 150 g rice | Glucose iAUC −30 to 40% |
| Trico et al. (19) | 8 | 50 g parmesan cheese + 50 g egg + 300 ml water |
−30′ | 500 ml water | 75 g oral glucose | Glucose iAUC −28% Peak glucose −49% |
| Trico et al. (38) | 17 | Protein- and fat-rich food before carbohydrate | Before 2 meals, 8 weeks | Reverse order | Isocaloric diet | HbA1c −0.3% *
Glucose CV −32% 2 h glucose rise −102% |
| Wu et al. (30) | 22 | 25 g whey protein + 250 ml water | −30′ | 250 ml flavored water | 400 g beef lasagna | Glucose AUC −1% *
Peak glucose−5% |
| Shukla et al. (39) | 16 | 150 g chicken meat + 170 g vegetables | −10′ | Reverse order | 90 g ciabatta bread + 120 ml orange juice | Glucose iAUC −53% Peak glucose −54% |
| Bae et al. (27) | 15 | 30 g protein- and fiber-rich bar + 150 ml water | −30′ | Reverse order | 100 g bagel + 70 g cheese + 210 ml orange juice | Glucose iAUC−25% |
| Watson et al. (40) | 79 | 17 g whey protein + 5 g guar gum + 150 ml water | 15′ before 2 meals, 12 weeks | 150 ml flavored water | 65 g powdered potato + 1 egg yolk + 20 g glucose + 200 ml water | HbA1c −0.1% Peak glucose −15% |
| Watson et al. (41) | 21 | 17 g whey protein ± 5 g guar gum + 60 mg sucralose + 150 ml water | −15′ | 60 mg sucralose + 150 ml water | 65 g powdered potato + 1 egg yolk + 20 g glucose + 200 ml water | Glucose iAUC −15% (independent of guar gum consumption) |
| IMPAIRED GLUCOSE TOLERANCE | ||||||
| Trico et al. (18) | 12 | 50 g parmesan cheese + 50 g egg + 300 ml water | −30′ | 500 ml water | 75 g oral glucose | Glucose iAUC −37% |
| Crouch and Slater (42) | 20 | 14.2 g almonds + 237 ml water | −30' | None | 75 g oral glucose | Glucose AUC −16% 2 h glucose −14% |
| Shukla et al. (43) | 15 | 100 g chicken meat + 285 vegetables + 15 ml olive oil | −20′ | Reverse order | 90 g ciabatta bread | Glucose iAUC −39% |
| NORMAL GLUCOSE TOLERANCE | ||||||
| Cunningham and Read (21) | 6 | 60 g margarine | −20′ | 300 ml beef consommé | 300 g mashed potato + 230 ml water | Glucose AUC −39% Peak glucose −18% Delayed glucose peak |
| Akhavan et al. (26) | 16 | 5–40 g whey protein + 400 ml water | −30′ | 300 ml water | 12 kcal/kg pizza + 500 ml water | Dose-dependent reduction in glucose AUC (~0–50%) |
| Akhavan et al. (44) | 10 | 10 or 20 g whey protein + 400 ml water | −30′ | 300 ml water | 12 kcal/kg pizza + 500 ml water | Mean glucose −4% |
| Trico et al. (18) | 12 | 50 g parmesan cheese + 50 g egg + 300 ml water | −30' | 500 ml water | 75 g oral glucose | Glucose iAUC −32% |
| Kuwata et al. (31) | 10 | 100 g mackerel fish or 79 g beef meat | 15′ | Reverse order | 150 g rice | Glucose AUC −19 to 30% * |
| Sun et al. (45) | 20 | 322 ml soy or dairy milk | −30′ | None | 91 g white bread + 322 ml water | Glucose iAUC −40 to 49% |
| Nishino et al. (46) | 8 | 60 g pork meat + 150 g vegetables + 5 ml olive oil | Before carbs | Reverse order | 150 g rice + 45 g pumpkin + 75 g orange + 150 ml water | Glucose AUC −48% * |
| Bae et al. (27) | 15 | 30 g protein- and fiber-rich bar + 150 ml water | −30′ | Reverse order | 100 g bagel + 70 g cheese + 210 ml orange juice | Glucose iAUC −18% |
| TYPE 1 DIABETES | ||||||
| Faber et al. (47) | 20 | 22 g cheese + 30 g turkey meat | −15′ | 22 g cheese + 30 g turkey meat in test meal | 2 slices bread + 15 g jam + 150 ml orange juice | Glucose AUC −19% *
Mean glucose −9% |
| GESTATIONAL DIABETES | ||||||
| Li et al. (29) | 33 each group | 18 g Inzone ®; Vitality (7.6 g protein + 1.8 g fat + 1.6 g fiber + 5.2 g carbs) + 250 ml water | −30′, each meal, 7 weeks | 18 g milk powder (3.5 protein + 1.1 g fat + 11.2 g carbs) + 250 ml water | Normal diet | Fasting glucose ~-17%2 h glucose ~-5% |
P < 0.05 unless otherwise specified.
*
P = ns. AUC, area under the curve; CV, coefficient of variation; iAUC, incremental AUC.